Linac - Linear Accelerator

The project aim was to convert a clinical linear accelerator
(6 MeV linac) into an adaptable research accelerator, capable of producing ‘on demand’ single-shot electron pulses
over a wide range of dose rates, and capable of photon generation using pulses at high repetition rates.
A variety of high dose rate, high dose, low LET photon and electron irradiation applications have been made possible.
Dynamics of protein recruitment and signalling processes at millisecond times may be studied by creating pure free
radical damage using sub-microsecond electron pulses.

Beam deflection power supplies are often required around accelerator beam lines to ‘trim’ the
direction of an accelerated particle beam or to shape it. Such power supplies often need to deliver relatively low currents and operate at
low voltages. We describe here a versatile Eurocard-
sized board which we use in the Institute’s electron linear accelerator.

Our Linear Accelerator endstation has been equipped with an inverted fluorescence microscope for analysis of the irradiated sample and a two-axis robot for fast transfer of the sample between the irradiation point and the microscope. A working
system requires flexible software control to co-ordinate the three sub-systems (accelerator, robot, microscope) which normally operate as stand-alone instruments.

Robotic sample handling systems often require some form of sample pickup and sample release
mechanism. We describe here an arrangement based on a solenoid electromagnet found useful for
transporting lightweight samples, such as cell holder/dish used in our irradiation system on an
accelerator.

There are numerous instances when small volumes (typically 1 litre) need to be
maintained at a fixed temperature above ambient. In biological science applications, the required
temperature is typically at around 37 degC. While there are numerous commercial solutions for
such applications, in general they are either very costly, ‘not quite right’ or, more often than not, are
part of a more complex system and thus hard to obtain. We describe here a simple solution which
may be of interest to others as it is made from readily available components and can be put together
in a couple of days. It was originally developed to maintain small biological samples at a constant
temperature within a microscope enclosure.

All ionising radiation producing sources must incorporate a personnel safety interlock system to restrict entry into potentially dangerous areas and to isolate/turn off the source at appropriate times; the arrangement used with the Oxford Linac is described here.